A common way for controlling users entries into a public transport network such as metropolitan or regional rail system consists in installing entry devices whose opening is activated by the user through the insertion of a ticket or access card into a control mechanism.
Currently, there are two types of entry devices. The first type is a three-arm turnstile whose rotation by 120.degree., which allows only one person to get through, is activated by the insertion of a ticket into the control mechanism. The major drawback of such a device is that users who want to commit fraud can easily step it over.
To overcome this drawback, a second type of entry device has been installed for controlling users, either as a stand-alone device, or along with the three-arm turnstile. This is a quite high one-panel or two-panel gate, whose automatic opening activated by the insertion of the ticket into the control mechanism is controlled by an electric or pneumatic system. Such devices present a number of drawbacks. First, existing control systems require quite a long time to run their cycle and activate the opening (approximately 0.5 to 0.7 sec.), and thus require that the ticket control mechanism be located at a distance from the automatic door, what reduces the users flow. Once activated, the opening is abrupt. As a result, the system is noisy and subjected, mainly at the end of the opening cycle, to vibrations that reduce its reliability. Moreover, a high power is required, what makes the system expensive. At last, since the user always faces a closed door before its opening, such devices may cause a very unpleasant feeling of confinement to the user.
The system disclosed by the patent U.S. Pat. No. 1,643,454 relates to a garage door activated by a motor driven crank. A roller interdependent with the crank runs into a slide interdependent with the door, thus transforming the crank rotation motion into the door translation. This way, half a turn of the crank enables to switch from the open position to the closed and locked position since the crank is stopped in a position slightly below a horizontal level. This system, that can be profitably used for automatic gate opening and closing, has however the drawback that driving and locking the door by only one crank requires a heavy door and/or rail guiding on the floor or a long recess housing since the opening or closing effort during acceleration and deceleration phases, and especially the effort for forcing the entry not lined up with the rod, applies on the guiding device a high torque that may cause the failure of the mechanism. Moreover, such a system does not provide for automatic and fast opening of the gate in case of an accidental power cut.